Cost-Effective Method to Perform SARS-CoV-2 Variant Surveillance: Detection of Alpha, Gamma, Lambda, Delta, Epsilon, and Zeta in Argentina.

SARS-CoV-2 variants with concerning characteristics have emerged since the end of 2020. Surveillance of SARS-CoV-2 variants was performed on a total of 4,851 samples from the capital city and 10 provinces of Argentina, during 51 epidemiological weeks (EWs) that covered the end of the first wave and the ongoing second wave of the COVID-19 pandemic in the country (EW 44/2020 to EW 41/2021). The surveillance strategy was mainly based on Sanger sequencing of a Spike coding region that allows the identification of signature mutations associated with variants.

Hepatitis B virus depicts a high degree of conservation during the immune-tolerant phase in familiarly transmitted chronic hepatitis B infection: deep-sequencing and phylogenetic analysis.

When intrafamilial transmission of hepatitis B virus (HBV) occurs, a virus with the same characteristics interacts with diverse hosts' immune systems and may thus result in different mutations to escape immune pressure. In this study, the HBV genomic characterization was assessed longitudinally after intrafamilial transmission using nucleotide sequence data of phylogenetic and mutational analyses, including those obtained by deep-sequencing for the first time. Furthermore, HBeAg-anti-HBe profile and variability of HBV core-derived epitopes were also evaluated.

Genotypes B and C hepatocellular carcinoma-associated hepatitis B virus pre-S mutants: their detection among F1b and A2 - but not F4 - isolates from Argentina.

Prevalence rates of hepatocellular carcinoma (HCC)-associated hepatitis B virus (HBV) pre-S mutants among most genotypes are still lacking. In this study, viral (sub)genotypes of 70 Argentine nucleotide sequences (33 newly obtained) were determined by phylogenetic analysis, and the presence of such mutants was assessed in the American continent for the first time. Nucleotide substitutions of the pre-S2 start codon were observed in 10% of the HBV/A2 sequences.

Successful interferon treatment in a patient chronically infected with hepatitis B virus carrying unusual S- (and P-) mutants in the presence of anti-HBs antibodies.

Background: Hepatitis B virus (HBV) immune escape mutants with point mutations within the S gene may arise during the natural course of HBV infection, due to a positive selection pressure exerted by the host immune response. Mutations within the immunodominant B and T cell epitopes of hepatitis B surface antigen (HBsAg) allow the resulting S-mutants to propagate even in the presence of neutralizing anti-HBs antibodies and the HBV-specific T-cell immune response.

Aim: To study the antiviral effect of Pegylated-interferon (Peg-IFN) in a patient with chronic hepatitis B carrying unusual S-(and P-) mutants in the presence of anti-HBs antibodies.